Electrical protective device.



I. N. MAHONEY & w. M AUSTIN.

ELECTRICAL PROTECTIVE DEVICE WITNESSES APPLICATION FILED APR. 3. I914,

Patented Apr. 30, 1918.

EC? 3 INVENTORS5I 7ATT0RNEY UNITED STATES PATENT OFFICE.

JOSEPH N. MAHONEY, OF WILKINSBURG, AND WALTER M. AUSTIN, 0F SWISSVALE,

PENNSYLVANIA, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND MANUFACTUR- ING-COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRICAL PROTECTIVE DEVICE.

Specification of Letters Patent.

Patented Apr. 30, 1918.

To all whom it may concern:

, Be it known that we, J OSEPII N. MA- HONEY, a citizen of the UnitedStates, and a resident of Wilkinsburg, in the county of Allegheny andState of Pennsylvania, and VALTER M. AUSTIN, a citizen of the UnitedStates, and a resident of Swissvale, in the county of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inElectrical Protective Devices, of which the following is aspecification.

Our invention relates to electrical protective devices, and particularlyto reversecurrent and underload tripping devices for circuitinterrupters.

The object of our invention is to provide a reverse-current andunderload tripping device of such construction that its magnetic fluxwill not traverse the pivotal parts and thus impede their operation.

Devices have heretofore been provided for tripping circuit interrupterswhen the direction of the current becomes reversed, as it frequentlydoes in interconnecteddistributing sytems, but such devices have beenexpensive to construct and the pivotal parts of the same have beenmagnetized to such an extent as to impair their accuracy of operation.

In our invention, we provide a simple and inexpensive reverse-currenttripping device which obviates the hereinbefore mentioned difliculty andwhich may be adjusted to operate when the current traversing a circuitfalls to any predetermined value.

Figure 1 of the accompanying drawing is a side elevational' view of acircuit interrupter embodying our invention, Fig. 2 is a frontelevational view of the device shown in Fig. 1, and Fig. 3 is a detailview, partially in section and partially in elevation,

of a device embodying our invention.

A circuit interrupter 1 is mounted upon a panel 2 and comprises two mainstationary contact members 3 and 4, a secondary stationary contactmember 5, a tertiary stationary contact member 6 and brackets 7 and 8upon which are pivotally mounted an arm 9 carrying a movable contactmember 10 for engaging the contact member. 6 and a second movable arm 11comprising a resiliently mounted member 12 for engaging the stationarycontact member 5, a laminated bridging member 13 that is pivotallymounted thereon, and a cam member 14, substantially as shown. The leverarm 11 extends through an opening in the lever arm 9 and they areconnected together by springs 15, for purposes hereinafter described. Anoperating lever arm 16 has a roller member 17 at one end thereof forengaging the cam member 14, and it also has two projections 18 and 19that extend substantially at right angles therefrom. Spiral springs 20connect the projection 18 to the arm 11, substantially as shown. Theprojection 19 of the operating lever arm 16 engages a latch 21 which istripped eithe by an overload tripping'coil 22, a manually operatedhandle 23 or by a reverse-current and underload tripping device 24 whichembodies our invention. a

The tripping device 24 comprises a coil 25 that is disposed around amagnetizable core member 26 and is connected to the stud of the contactmember 4 and to an auxiliary terminal 27. The magnetizable core member26 is of substantially U-shape and has depending from each leg thereoftwo auxiliary core members 28 and 29 and 30 and 31, respectively, uponwhich are respectively disposed series-connected windings 32, 33, 34 and35 the circuit comprising which is connected in shunt relation to thecircuit that is to be protected. The windings 32, 33, 34 and 35 are soconnected that they form alternate magnetic poles of which the coremembers 29 and 31 have the same polarity, and the core members 28 and 30have a polarity which is opposite to that of themembers 29 and 31. Twobrackets 36 are provided, and, pivotally mounted upon these brackets isa movable member 37 upon the downwardly is the greatest by reason of themagnetization of 'the in agnetizable core member 26, as hereinbeforementioned When the current flowing through the coil 25 reverses indirection, by reason of the common faults so often perceptible ininterconnected distributin systems, the magnetizable member 26 will beattracted more strongly in the opposite direction from that in which itis normallv attracted and thus the movable member 38 will be quicklyover-balanced and moved upwardly to operate the latch 21 through the rod43, bell crank lever and rod 46 to trip the circuit interrupter 1.

The operating lever 16 of the circuit interrupter 1 moves upwardlly whenthe projection 19 is released by the latch 21 to allow the roller 17 tomove over the face of the cam member 14 and thus cause the springs 20 tooperate the bridging contact member 13 and the secondary contact. member12, successively. The disengaging of these contact members forces thedisengagement of the contact members 6 and 10, as will be readilyunderstood.

The reversed current at which the circuit interrupter 1 is tripped maybe adjusted by with respect to the pivotal point of the member 37 ,aswill be understood.

Since the magnetizable member 38 is disposed between the poles of theseveral aux iliary electromagnets, the magnetic lines of force will nottraverse the bracket 36 to impede the operation of the movable member 37by magnetizing the pin 47 upon which it is mounted. A stop 48 is locatedon one of the brackets 36 for preventing too great a movement of themember 38 in a downwardly direction, as willv be readily seen.

The windings may be omitted from one of the alternately disposed coremembers on each leg of the core member 26, thus providing two consequentpoles. The operation of the device with the two windings will besubstantially the same as was described with respect to the device withthe four windings.

By adjusting the position of the weight 39 and the position of thescrews 42, the device may be caused to operate when the currenttraversin the coil 25 falls below a predetermined va ue, as will beunderstood.

means electromagnets depending therefrom to constitute alternatemagnetic poles, a movable core member pivotally mounted between the coremembers of said electromagnets, and means for so balancing the saidpivotally mounted core member that, when the magnetic lines of forcechange in the said magnetizable core member, the pivotally mounted coremember is attracted in a predetermined direction.

2. In a circuit protective device, the combination with a circuitinterrupter, of a tripping device therefor comprising a magnetizablecore member in operative relation to one terminal of the said circuitinterrupter, a'plurality of projections on said magnetizable coremember, windings for the said projections for forming alternate magneticpoles, a pivotally mounted movable member disposed between theprojections of said magnetizable core member, and means whereby thepivotally mounted movable member trips the circuit interrupter when thecurrent reverses therein.

8. In a circuit protective device, the combination with a circuitinterrupter, of a reverse-current tripping device therefor comprising amagnetizable core member, means for magnetizing the core member inaccordance with the current traversing the circuit, auxiliary coremembers depending from the core member, windings for the auxiliary coremembers for forming alternate ma netic poles, a movable member pivotallymounted at a point intermediate its ends, a magnetizable member locatedat one end thereof, and means whereby the said movable member will tripthe said interrupter when the current reverses therein.

4. In a circuit protective device, the com bination with a circuitinterrupter, of a reverse-current tripping device therefor comprising amagnetizable core member adapted to be magnetized in accordance with thecurrent traversing the circuit, auxiliary core members dependingtherefrom, windings disposed on the said auxiliary core-members toconstitute alternate magnetic poles, a movable member pivotally mountedat a point intermediate its ends, a magnetizable member located at oneend thereof, a counter-balance Weight operatively connected thereto, andmeans whereby said movable member will trip the said interrupter whenthe current reverses therein.

5. In a circuit protective device, the combination with a circuitinterrupter, of a re verse-current tripping device therefor comprising amagnetizable.core member adapted to be magnetized in accordance with thecurrent traversing the circuit, auxiliary core members dependingtherefrom, windings for the said auxiliary core members adapted toproduce alternate magnetic poles, a movable member pivotally mounted ata point intermediate its ends, a magnetizable member located at one endthereof, a counter-balance weight operatively connected thereto, meansfor adjusting the relative position of said counterbalance weight, andmeans whereby said movable member will trip said interrupter when thecurrent therein reverses.

6. In a circuit PI'OtGClDlVB1d6VlC8, the combination with a circuitinterrupter, of a re- Y verse current tripping device thereforcomprising a magnetizable core member, means for magnetizing the same inproportion to the current traversing the said interrupter,

two auxiliary core members depending from each pole of said magnetizablecore member, means for magnetizing said auxiliary core members 'toconstitute alternate mag netic poles, brackets, ,a movable :rnemberpivotally mounted on said brackets at a point intermediate its ends, anda magnetizable member on the inner end of said movable member anddisposed between the two auxiliary core members on each pole of saidmagnetizable core member.

7. A tripping mechanism for a circuit interrupter comprising amagnetizable core member adapted to be energized in accordance with thecurrent traversing the interrupter, a plurality of laterally-extendingcore members operatively connected thereto,

means for energizing the laterally-extending core members to constitutealternate magnetic poles, and a pivotally-mounted movable core memberdisposed between the laterally-extending core members and adapted to beactuated when the current traversing the circuit interrupter reverses indirection.

8. The combination with a circuit interrupter, of a magnetizable coremember energized in accordance ,withthe current traversing the circuitinterrupter, a plurality of projections on the magnetizable core member,means for energizing the projections to constitute alternate magneticpoles, and a pivotally-mounted movable core member disposed between thesaid projections and adapted to be actuated under predeterminedconditions.

9. The combination. with a circuit interrupter, of a reverse-currenttripping device therefor comprising a magnetizable core member adaptedto be energized in accordance with the current traversing theinterrupter, auxiliary core members projecting thereon, means forenergizing the said auxiliary core members to constitute alternatemagnetic poles, and a movable magnetizable member pivotally mounted at apoint intermediate its ends and adapted to be actuated when the currentreverses in the circuit interrupter.

In testimony whereof, we have hereunto subscribed our names this 31stday of March, 1914:.

J OSEPI-I N. MAHONEYQ WALTER M. AUSTIN.

Witnesses: J N0. MCKECHNIC, B. B; Hmns.

